Organo-silicon esters and materials treated therewith



Patented Aug. 20, 1946 ORGANO-SILICON ESTERS AND MATERIALS TREATEDTHEREWITH Arthur J. Barry,

The Dow Chemical Com corporation of Michiga Midland, Mich., assignor topany, Midland, Mich., a 11 No Drawing. Application December 10, 1943.Serial No. 513,746

6 Claims. 1

wherein R in each instance represents a radical selected from the classconsisting of hydrocarbon and hydrocarbonoxy radicals and at least one Rrepresents such radical containing at least 8 car- 'bon atoms andselected from the class consisting of alkyl and alkoxy radicals, Rrepresents a hydrocarbon radical and n is an integer not greater than 3.When in the above general formula n is greater than 1, the radicalsrepresented by the symbols R may be the same or different and, when n isan integer less than 3, the radicals represented by the symbols R may bethe same or different. It also concerns the treatment of solidhydrophilic materials with such organo-silicon esters for purpose ofmodifying a surface of such normally hydrophilic material to render itrepellent to water. The invention comprises the resultantwater-repellent solid products.

The organo-silicon esters having the above general formula vary frommobile liquids to waxlike solids. They may be hydrolyzed with water toremove the ester radicals and form organosilicols which often undergointermolecular condensation reactions to form viscous liquid or solidproducts of high molecular weight; or they may be reacted with hydroxycompounds, e. g. alcohols, phenols, or cellulose, to form correspondingalkoxy-siiicon derivatives of such hydroxy com pounds. Accordingly, thenew organo-silicon esters are useful as starting materials for thepreparation of a variety of derivatives thereof.

The organo-sillcon esters provided by the invention are especiallyuseful as agents jor the treatment of solid hydrophilic materials,particularly cellulosic materials, to modify the surface thereof andrender such materials repellent to water. In my copending applicationSerial No. 513,745, filed concurrently herewith, it is disclosed thatorgano-silicon halides may be applied to and reacted with the hydroxylgroups at the surface of solid hydrophilic materials, e. g. metals,glass, wood, or cellulosic substances, to modify the surface of suchnormally hydrophilic materials and render them repellent to water. It isalso pointed out that during such treatment a chemical reaction occurswith liberation of hydrogen halide and, apparently, with resultantchemical bonding of organo-silicon radicals to the hydrophilic material.The surface of the latter is thereby modified and is rendered repellentto water. However, in said copending application it is taught that thehydrogen halide formed in the treatment tends to act upon and weakencellulosic materials and that in treating the latter with organo-siliconhalides care should be taken to remove the hydrogen halide as soon aspossible so as to limit the destructive action which takes place.

I have now found that the organo-siiicon esters having the generalformula hereinbefore mentioned may similarly be employed for thetreatment of hydrophilic solid materials to modify the surface of thelatter and render it repellent to water. In such treatment theorgano-silicon esters apparently react chemically with hydroxyl groupsat the surface of the hydrophilic material to liberate an organiccarboxylic acid and chemically affix organo-silicon radicals to thehydrophilic base member. However, the invention is not limited to thistheory as to the reason for the result which is obtained. Thewater-repellent film which is formed at the surface of the base memberis very thin, and the appearance of the base member is usually notaltered. The waterrepellent film thus provided on a normally hydrophilicbase member is absorptive to organic liquids. Paints, varnishes,lacquers, and the like usually adhere more firmly to such film than tothe hydrophilic base member itself; hence, the latter may advantageouslybe provided with such film prior to being painted or varnished.

The organo-silicon esters may be applied to a variety of normallyhydrophilic solid materials, e. g. iron and its alloys, magnesium andits alloys, other metals, wool, wood, cotton, or cellulose esters orothers, etc., to modify surfaces of such materials and render themwater-repellent. Apparently all such hydrophilic materials have reactivegroups, usually hydroxyl and in some instances amino radicals, at thesurface so that in all such treatments a chemical reaction may occurwith resultant bonding of organo-silicon radicals to the surface of thehydrophilic material under treatment. That chemical bonding probablydoes take place is evidenced by the fact that the treated material doesnot readily lose its Water-repellent properties when washed withsolvents for the organo-silicon ester employed in the treatment.

The organo-silicon esters may be applied with particular advantage tocellulosic materials such as wood, cotton, cellulose acetate, or ethylcellulose, etc., since the organic carboxylic acid which is liberated bythe treatment has little or no detrimental action on cellulosicmaterials; hence. special precautions for rapidly removing the acid asit is formed are not required. For this reason, the organo-siliconesters of this invention are superior to organo-silicon halides asagents for treating cellulosic materials to render them water repellent.

The requirement that the organo-silicon esters contain on the siliconatom at least one alkyl or alkoxy radical having 8 or more carbon atomsis important, since I have found that the permanence and durability ofthe water-repellent film which is formed at the surface oi a.iwdrophilic material when the latter is treated with such ester islargely dependent on the length of the largest allryl or alkoxy radicalattached to the silicon atom of the ester. For instance, a hydrophilicmaterial such as cotton may be rendered water repellent by treatmentwith a lower organosilicon compound such as triethyl-silicon acetate,triethoxy-silicon acetate, tripropoxy-silicon acetate,tri-isopropoxy-silicon acetate, tributoxysilicon acetate, ordimethyl-silicon dichloride, etc., but the water-repellent film which isformed is readily removed by washing, particularly with soapy water. Incontrast, the higher organosilicon esters provided by the invention,when applied to cotton or other hydrophilic materials, form a far morepermanent and durable waterrepellent film which is not readily removedby washing. Furthermore, when, after prolonged use or extensive washing,the water-repellent film starts to fall, e. g. the hydrophilic basemember becomes wetted in spots, the goods may again be rendereduniformly water repellent by drying and washing them with an organicsolvent such as benzene, toluene, carbon tetrachloride, ethylenechloride, or propylene chloride, etc. It appears, therefore, that suchultimate failure of the water-repellent film formed by the higherorganosilicon esters oi. this invention is not due to destruction of thehim but, more probably, to a change in the orientation of theorgano-silicon groups at the surface or the hydrophilic base member andthat the subsequent washing with an organic solvent causes are-orientatlon of such groups so as to again render the treated materialuniformly repellent to water. The invention is, of course, notrestricted by this theory as to the reason for the results obtained. Ingeneral, the permanence and durability of the water-repellent filmsformed at the surface of hydrophilic base members increases withincrease in the number of carbon atoms in the largest alkyl or alltoxyradical attached to the silicon atom of the organo-silicon ester used informing such film and the organo-silicon esters containing such alkyl oralkoxy group having at least 12 carbon atoms are preferred for thepurpose.

The organo-silicon esters may be prepared by the reaction 01' a salt ofan organic carboxylic acid with a higher organo-silicon halidecorresponding to the ester product desired. Methods for makingorgano-silicon halides are well known, but, since many of the higherorgano-silicon halides used in preparing the esters are themselves newcompounds, the general methods for making the halides will be mentionedbriefly. Alkyl silicon halides, e. g. octyl-silicon trichloride ortri-dodecyl-silicon chloride, etc., may be prepared by reacting an alkylmagnesium halide,

e. g. octyl-magnesium chloride or dodecyl-mag- 75 peratures below nesiumbromide with a silicon tetrahallde, e. a. silicon tetrachloride. Usuallyan ether is used as a medium for the reaction. The reactants arepreferably employed in approximately the stoichiometric proportions, andthe product is purifled by distillation. Alkoxy silicon halides may beprepared by reacting an alcohol, e. g. octyl alcohol or dodecyl alcohol,with a polyhalo-silicon compound such as silicon tetrachloride, silicontetrabromide, diethyl-silicon dichloride, or phenyl-silicon trichloride.Such reaction usually occurs readily at room temperature or below andmay be carried out nearly quantitatively by heating the mixture, e. g.to -l00 C., after the initial vigor of the reaction has subsided. Thereactants are employed in proportions such as to replace at least one,but not all, of the halogen atoms of the polyhalo-silicon compound withalkoxy groups. For instance, tridodecoxy-silicon chloride may beprepared by reacting 3 molecular equivalents of dodecyl alcohol with onemole of silicon tetrachloride and di-dodecyl-dodecoxysilicon chloridemay be prepared by the reaction of equimolecular amounts oi dodecylalcohol and di-dodecyl-silicon dichloride. Usually, a solvent such asbenzene, ligroin, or petroleum ether is used as a reaction medium andthe mixture is cooled, e. g. to 10 C. or lower, in the early stages ofthe reaction.

The organo-silicon esters 01' this invention are preierably prepared bytreating an organo-silicon halide, having on the silicon atom an alkylor alkoxy group containing at least 8 carbon atoms, with a metal salt ofan organic carboxylic acid and heating the mixture to a reactiontemperature. Examples of organo-silicon halides which may be employed asreactants are octylsilicon trichloride, decyl-silicon trichloride,dioctyl-sllicon dichloride, tri-dodecyl chloride, dimyricyl-silicondichloride, octyloxy-silicon trichloride, di-octyloxy-silicondichloride, tri-octyloXy-siiicon chloride, dodecoxy-silicon trichloride,phenyl-octyl-dodecoxy-silicon chloride, di-dodecyl-dodecoxy-siliconchloride, dodecyimyricyloxysilicon dichloride, etc. In place of thechlorides the corresponding organo-silicon bromides may be used. Amongthe various salts of organic carboxylic acids which may be used asreactants are sodium formate, potassium acetate, sodium propionate,potassium butyrate. sodium valerate, sodium crotonate, sodium oleate,sodium stearate, sodium benzoate, or sodium cinnamate, etc. Salts ofpolycarboxylic acids may similarly be used to form neutralorgano-silicon esters thereof. The salt is employed in amount at leastas great as that theoretically required to displace the halogen atoms oithe organo-silicon halide reactant and it preferably is used in excess.Usually, two chemical equivalent weights or more of the salt is used peratomic weight of halogen in the organo-silicon halide reactant. In placeof the salts of the carboxylic acids, the free acids may, thoughsomewhat less conveniently, be used as reactants. One part by volume ormore of an inert organic solvent such as petroleum ether, iigroin,benzene, or toluene, etc., is preferably employed, per part of theorgano-silicon halide, as a medium for the reaction, but the reactionmay be carried out in the absence of such medium.

The mixture is heated under reflux, or in a closed container, to areaction temperature, usually of from 60 to C., for a time sufllcientfor completion of the reaction. Reaction temor above those Justmentioned may be used. The reaction is usually complete after from to 20hours oi heating at about 100 C. The product is then separated from thesodium chloride, or other inorganic halide, formed in the reaction byusual procedure, e. g. filtration 6 heating at said temperature wassumcient. The mixture was then filtered to remove the sodium chlorideformed in the reaction, after which the solvent was distilled from thefiltrate to obtain the organza-silicon ester product as the residue.

5 or extraction oi the product from the reaction In some instances afurther quantity of the solmixture with an organic solvent such aspetrovent was added prior to the filtration in order to leum ether orligroin followed by vaporization dissolve the ester product, but usuallythe quanoi' the solvent from the product. By such procetity of solventemployed as the reaction medium dure, a neutral organo-silicon ester maybe 010- 10 was suillclent to maintain the product in solutained in aconcentrated, or substantially pure, tion. Many of the organo-siliconester products form. In some instances, the product may be thus obtainedwere further purified by fractional further purified by fractionaldistillation under distillation, but some of the products were of toovacuum, but many oi the organo-silicon esters of hi h il p t t p t st awithout the present invention are high-boiling compounds the occurrenceof decomposition. In all inwhich tend to undergo decomposition whenfracn the products were obtained in a highly tionally distilled.concentrated form satisfactory for use in the The following examplesdescribe a number or treatment of fabrics or other solid hydrophilicways in which the principle of the invention has materials to rendersuch materials repellent to been applied, but are not to be construed as11 water. The following table names the reactants iting the invention:employed in preparing each organo-silicon ester Emu! 1 product, statesthe molecular proportions in which they were used, describes the esterproduct. and In each of a series of experiments. a higher states whetherthe product is distilled. Since cream-si icon este w s p epared byheating a many of the organo-silicon halides employed in mixture of asodium Salt 0! an 0 a bo ylic preparing the ester products arethemselves new acid and a solution of an organo-silicon chloridecompounds, the table includes a statement as to in an equal volume ormore. usually about 1.5 the kinds and proportions of reactants used inparts by volume, of petroleum ether. or toluene, making such halides.The procedures for making under reflux at about 100 C. until theformathe organo-silicon halides have been presented io an Precipitationof Sodium chloride as no in the foregoing general description of theinvenlonger observed. In most instances, 16 hours 01' tion.

Table I Reactants Organo-silicon eater product Organs-silicon halideSalt Run Product No. distilled Prepared h-om Name Description Kind MolesKind Moles Compound Moles Tl'ldodeeo siliicil 1 1* id d 11- Li id i l tN m... s. I inmates... 3 i 3 20863.3... a..." Liquid of pale Yes i mral- SlCh 1 T d d ill. 4 2 I {Dodecyl alcohol... 3 isodmmmtate" 4 egnggfgg mm. with decomposition. 3... Trl-octadecoxy 1 {Si k l d0 4Trl-octadccoxysil- AwhitewaxolM. No. 4 Daillotznghlorlde. g ci idecylalcohol. i l icon acetate. P. 413 C.

0C 8 ccoxy- 4 Dl-octadecoxy- A soft war of yel- No. filiiiltild. tugs;still i i 1mm slcli 1 .'i 0ctadecoxy-do- Octadeeoxy-do- A ellow liquid.No.

y-a ma} 1 ggfif gg fifif; imli 4 de xy-p p xyy silicon chloride. mpmpylgleam], v I silicon acetate. 6 Di-dodecoly 8115 1 Sick l d 8{Dl-dodeooxy sili Nearly colorless No.

con dichloride. Dl-dodecyi alcohol 2 o con diacctateJ liquid (lighttan). 7... Dodecoxysilicou 1 SIC]; l do w 7 Dodccoxy silicon Anearlycolorless N0.

trlchloride. Dodecyl alcohol... 1 tri-acetateJ liquid. Tri-myric 10!? 1SlCh 1 do 4 Trimyriciloxy sili- A white warlike No.

silicon ch orldc. Myricyl alcohol." 3 con acetate. solid. 9 Tri-oct loxysili- 1 SlCli l d0 4 'lri-octyloxy sill- A liquid of light No, 96hr.0011 c iOridB- 3 con acetate. amber color. reaction pcrlo 10Di-dodeeoxy-isorise-am l silicon i Di-dodccoxy-iso- Allquid of brown 0.

amyl silicon 1 trich oride. .do 3 amylsiliconacecolor. chloride. Dodecylalcohol. 2 late. fi fl y- -p e y Silicon 1 Dodecoxy-di- A nearlycolorless No.

phenyl silicon l dichloride. ...do 3 phenyl silicon liquid. chloride.gtdlecyl alcohol. i acetate. 12.. Trl-dodecyl slli- Tri-dodecy] sill- Aliquid of pale No con chloride. l gg g' fiffi' 3 3 con acetate. yellowcolor. 13' D d l silicon Sic! 1 d i i i r? 1 {node'cfi nigiit 1 .do 6 Ytrlehlorldc. a tale and Di l ilq 2 5 Cg HuSiChCCHg. l4. Dodecyl di hen-5 Dodecyldihenyl A liquid of light No.

yi silico ii db} 1 gz g n I do. 2 silicon a ienate tan color. chloride.g i f c. F. 0-5560). i5..,. Dodecoxy-di- Dodccoxy silicon 1 Dodecoxy di-A liquid of tan No.

octyloxysilicon l trichloride. ISodiumstearate i octyloxy silicon color.chloride. Sec-octyl alcohol. 2 stearatc.

Products believed to contain compounds iormed by loss oi one or moreacetate radicals.

7 Exmu:

In each of a series of experiments, a strip of cotton broadcloth, havinga count of 80 x 160 threads per inch, was immersed for minutes in asolution containing 3 per cent by weight of the organo-silicon esternamed in Table II dissolved in a dry-cleaning liquid consisting of amixture of ethylene chloride and propylene chloride. The cloth was thenpressed with a flatiron heated to about 250" C. until substantially freeof the dry-cleaning fluid and thereafter for about two minutes to assurereaction of the organosilicon ester on the fabric. Different strips ofthe treated cloth were subjected to diflerent kinds of washingoperations, after which each was dried, i. e. until substantially freeof the wash liquor, and tested for water repellency by the "hydrostaticmethod described by Slowinske in Am. Dyestuif Reporter 7 (1941). Thekinds of washing operations employed in the different experiments arenamed in the table and are as follows: (i) a hand wash with water whichcontained 0.5 per cent by weight of soap (the hand soap marketed asPalmolive was used) and (2) subjecting the treated material toextraction for 18 hours in a Sohxlet extractor using the abovementioneddry-cleaning fluid, i. e. a mixture of ethylene chloride and propylenechloride, as the extractant. The purpose of the treatment with thedry-cleaning fluid was to flnd whether said fluid, which is an excellentsolvent for the organosilicon esters applied to the pieces of fabric,would extract from the latter the ingredient causing it to be repellentto water. Failure of the dry-cleaning fluid to destroy thewater-repellent property of a fabric would be evidence that theorgano-silicon ester had reacted chemically with the fabric. The tablestates the repellency toward water of each treated fabric in terms ofthe hydrostatic pressure in centimeters of water 8 esters are somewhatmore effective and more stable against the action of soapy water thanare the fllms formed by treating fabrics with correspondingalkoxy-silicon esters.

Exmu3 A number of strips of cotton broadcloth, having a count of xthreads per inch, were treated with dodecyl-di-phenyi silicon acetate,or with tri-dodecyl silicon acetate, and the treated fabrics werepressed with a heated flatiron, as in Example 2. However, the differentpieces of treated fabric were then subjected to washing procedures whichwere even more severe than those employed in Example 2. One of thewashing procedures was the standard soap and water washing rationdescribed on page of the AATCC book of Standard Test Methods." Anotherprocedure involved subjection of a fabric to extraction forapproximately 18 hours in a Sohxlet extractor while using thedry-cleaning fluid mentioned in Example 2 as the extractant and thenfreeing the fabric of the dry-cleaning fluid and subiecting it to saidstandard washing operation with soap and water. A third procedureinvolved extracting a fabric with the dry-cleaning. fluid and thensubjecting it to the standard washing operation with soap and water, asjust described, and next again subjecting it to extraction with thedry-cleaning fluid for a period of about 18 hours in a Sohxletextractor. A treated fabric, after being washed by one of these threeprocedures, was dried and tested for water repellency by the"hydrostatic method mentioned in Example 2. Table III names the alkylsilicon esters used for the treatment of fabrics in the differentexperiments and gives the water repellency of the treated fabrics afterbeing subjected to the respective washing procedures just described. Thewater repellency is expressed in terms of the hydrostatic pressure, incentimeters of water, which the fabric withwhich the fabric withstoodbefore leakage ocstood before leakage occurred.

Table III H10 repellency of treated fabric alter- 3, Orgsno-lillcon am:am. D cleaning f fim soap and fol wed by at ma d water std. soap and ras;

wash water wash dnmleantng 1 Dodecyl-di-pbenyi-silicon scetsta. l4 l0 l62 Trl-dodeeyl-sllicon acetate l0 i0 30 curred during the test of thefabric by the abovementioned hydrostatic method.

From the above data it appears that the drycleaning fluid has th effectof orienting the or- Table II H10 repellency of treated fabric after-Rnn or gene-silicon ester No wasb- Walling witl E ia??? cleaning uld l-Tri-octyloxy-silicon acetate 1 1 Not tested ill 2 Dodecylory-sillcontri-acetate 18 1| 35 3 DI-dodecylory-sillcon iii-acetate.-- l0 l6 r- 344-.-. Tri-dodeeox -si.llcon acetate 19 ll 34 5..." Dodeco -dphenyl-sllicon acetate 16 Not tested 24 6 'lrl-oc eoyloxy-sillconacetate... 21 20 32 7--- Dodecyl-di-phenyl-sllicon acetate 23 Nottested" 34 a-.- Tri-dodecyl-silicon acetate 32 ..do 38 From a comparisonof Run 4 of Table II with Run 8 and of Run 5 with Run '7, it will benoted that the water-repellent films formed on fabrics by treating thelatter with higher alkyl silicon gano-silicon radicals at the surfacesof the fabric so as to increase the repellency toward water.

Other modes of applying the principle of the 76 invention may beemployed instead of those explained, change being made as regards thestep or steps herein disclosed provided th step or steps set forth byany 0! the following claims or the equivalent of such stated step orsteps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An organo-silicon ester having the general formula:

10 2. An organs-silicon ester having the general formula:

0 n.si( o-ii-n')...

wherein R in each instance represents an alkoxy radical containing atleast 8 carbon atoms, R represents an alkyl radical, and n is an integernot greater than 3.

0 m 3. Tri-octadecyloxy-silicon acetate. E 4. An crgano-siilcon esterhaving the general as o- R' 0- iormula:

0 wherein R in each instance represents a radical R g selected from theclass consisting of hydrocarn ban and hydrocarboncxy i d t least onewherein R is an alkyl radical having at least 8 R represents suchradical containing at least a carbon atoms, repr n s n alkyl r l andcarbon atoms and selected from the class con- Me an integer not greaterthan 3. sisting of alkyl and alkoxy radicals, R represents Dodccyl-dl-phyll n acetatea hydrocarbon radical, and n is an integer not an 6.Tri-dodecyl-sillcon acetate. greater than 3. ARTHUR J. BARRY.

Disclaimer 2,405,988.Arthm- J. Barry, Midland, Mich. ORGANO-SHJCON EsmeAND MATERIALS TREATED Tnannmm. Patent dated Aug. 20, 1946. Disclaimerfiled June 20, 1951, by the assignee, The Dow Ghemical 00mpang Herebyenters this disclaimer from the scope of said patent: In claim 1, estersof the formula given wherein the symbol R represents an alkyl radical;

claim 4 in its entirety.

[Oficz'al Gazette July 31,1951] plained, change being made as regardsthe step or steps herein disclosed provided th step or steps set forthby any 0! the following claims or the equivalent of such stated step orsteps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An organo-silicon ester having the general formula:

10 2. An organs-silicon ester having the general formula:

0 n.si( o-ii-n')...

wherein R in each instance represents an alkoxy radical containing atleast 8 carbon atoms, R represents an alkyl radical, and n is an integernot greater than 3.

0 m 3. Tri-octadecyloxy-silicon acetate. E 4. An crgano-siilcon esterhaving the general as o- R' 0- iormula:

0 wherein R in each instance represents a radical R g selected from theclass consisting of hydrocarn ban and hydrocarboncxy i d t least onewherein R is an alkyl radical having at least 8 R represents suchradical containing at least a carbon atoms, repr n s n alkyl r l andcarbon atoms and selected from the class con- Me an integer not greaterthan 3. sisting of alkyl and alkoxy radicals, R represents Dodccyl-dl-phyll n acetatea hydrocarbon radical, and n is an integer not an 6.Tri-dodecyl-sillcon acetate. greater than 3. ARTHUR J. BARRY.

Disclaimer 2,405,988.Arthm- J. Barry, Midland, Mich. ORGANO-SHJCON EsmeAND MATERIALS TREATED Tnannmm. Patent dated Aug. 20, 1946. Disclaimerfiled June 20, 1951, by the assignee, The Dow Ghemical 00mpang Herebyenters this disclaimer from the scope of said patent: In claim 1, estersof the formula given wherein the symbol R represents an alkyl radical;

claim 4 in its entirety.

[Oficz'al Gazette July 31,1951]

